444 research outputs found
Superpartner Solutions of a BPS Monopole in Noncommutative Space
We construct U(2) BPS monopole superpartner solutions in N=2 non-commutative
super Yang-Mills theory. Calculation to the second order in the noncommutative
parameter shows that there is no electric quadrupole moment that is
expected from the magnetic dipole structure of noncommtative U(2) monopole.
This might give an example of the nature of how supersymmetry works not
changing between the commutative and noncommutative theories.Comment: 8 page
Advanced control strategies toward achieving nearly-zero energy consumption in buildings
In this paper the main concept and results of the PEBBLE Project are presented: PEBBLE is an ongoing FP7
Project aiming at the development of advanced ICT tools to support the operation of nearly-zero- and positive energy buildings. In the design and operation of such buildings a pragmatic target is maximization of the actual net energy produced (NEP) by intelligently shaping demand to perform generation-consumption matching. With
the belief that maximization of the NEP for Positive-Energy Buildings is attained thru Better ControL decisions (PEBBLE), a control and optimization ICT methodology that combines model-based predictive control and cognitive-based adaptive optimization is presented. There are three essential ingredients to the PEBBLE system: a) thermal simulation models; b) sensors, actuators, and user interfaces; and c), generic control and optimization tools. The potential for energy savings using advanced control strategies is illustrated using simulation-based studies: there are significant benefits in terms of energy-performance of using advanced control strategies, compared to traditional rule-based ones. Ongoing work about demonstration and evaluation of the PEBBLE system in three real world buildings is described
Comparing the impact of different thermal comfort constraints on a model-assisted control design process
In the design of supervisory controllers for managing energy in buildings, modelbased
control design approaches have recently attracted significant attention. The
control-design problem in these cases is typically posed as a constrained
minimization problem: given a simulation model acting as a surrogate of the
building, identify a controller that minimizes a cost function, say energy, subject to
the constraint that thermal comfort stays within acceptable levels. The use of a
thermal comfort model can be the means for estimating comfort so that the
mathematical programming problem can be formulated. In the present paper, we
investigate how the choice of thermal comfort model affects the quality of the
resulting controller. We consider a building simulated in EnergyPlus and design,
under the same conditions, controllers using three different thermal comfort models:
the model of Fanger, the two-node Pierce model, and the KSU two-node model. A
comparative study is performed to draw conclusions upon the effects that this
selection has with respect to the performance of the resulting controller
Gauge Field Fluctuations and First-Order Phase Transition in Color Superconductivity
We study the gauge field fluctuations in dense quark matter and determine the
temperature of the induced first-order phase transition to the
color-superconducting phase in weak coupling. We find that the local
approximation of the coupling between the gauge potential and the order
parameter, employed in the Ginzburg-Landau theory, has to be modified by
restoring the full momentum dependence of the polarization function of gluons
in the superconducting phase.Comment: 5 pages, 1 figure, Revtex, we have modified our conclusions for the
metallic superconducto
Gauges in the bulk
We present a general framework for nonparallel brane worlds and use it to
discuss the nonlinear radion problem. By imposing the Einstein frame as a gauge
condition we are able to give the effective action for both Minkowski and
(A)dS branes. In particular we find the nonlinear radion does not
disappear in the second Randall-Sundrum model.Comment: LaTeX file of 14 page
Higgs Mechanism in String Theory
In first-quantized string theory, spacetime symmetries are described by inner
automorphisms of the underlying conformal field theory. In this paper we use
this approach to illustrate the Higgs effect in string theory. We consider
string propagation on M^{24,1} \times S^1, where the circle has radius R, and
study SU(2) symmetry breaking as R moves away from its critical value. We find
a gauge-covariant equation of motion for the broken-symmetry gauge bosons and
the would-be Goldstone bosons. We show that the Goldstone bosons can be
eliminated by an appropriate gauge transformation. In this unitary gauge, the
Goldstone bosons become the longitudinal components of massive gauge bosons.Comment: 12 pages, Te
Is gluonic color-spin locked phase stable?
We study the gluonic color-spin locked (GCSL) phase in dense two-flavor quark
matter. In this phase, the color and spatial rotational symmetries are
spontaneously broken down to SO(2)_{diag} with the generator being an
appropriate linear combination of the color and rotational ones. The Meissner
masses of gluons and the mass of the radial mode of the diquark field in the
GCSL phase are calculated and it is shown that this phase is free from the
chromomagnetic and Sarma instabilities in the whole parameter region where it
exists. The GCSL phase describes an anisotropic color and electromagnetic
superconducting medium. Because most of the initial symmetries in this phase
are spontaneously broken, its dynamics is very rich.Comment: 5 pages, 4 figures, clarifications added, to appear in Phys. Rev. D
(Rapid Communications
State–of–the–art report on nonlinear representation of sources and channels
This report consists of two complementary parts, related to the modeling of two important sources of nonlinearities in a communications system. In the first part, an overview of important past work related to the estimation, compression and processing of sparse data through the use of nonlinear models is provided. In the second part, the current state of the art on the representation of wireless channels in the presence of nonlinearities is summarized. In addition to the characteristics of the nonlinear wireless fading channel, some information is also provided on recent approaches to the sparse representation of such channels
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